Piper Navajo PA-31 Service Manual page 92

PIPER NAVAJO SERVICE MANUAL
3-12. INSPECTION OF FUEL SELECTOR AND CROSS FEED VALVE CONTROL CABLES. (Refer to
Figure 3-5.) At each 100 hour inspection of the airplane, inspect the fuel selector and cross feed valve control
cable wires. Conduct the inspection as follows:\
a. Remove the access cover located on the underside of the fuselage, below the fuel selector panel just
ahead of the main spar and the access panel between the fuselage and the underside of the wing.
b. Visually check control cable wires at swivel fittings for indications of binding, kinks or bends: have
someone in cockpit operate fuel controls while mechanic inspects wires at swivel fittings.
c. Replace cable(s) exhibiting any of the above conditions.
d. Check adjustments of selector valve and cross feed valves per Section IX.
e. Replace access panels and covers.
3-13. INSPECTION OF AILERON SPROCKET AND CHAIN. (Refer to Figure 3-6.)
a. To determine if corrective action is required because of misalignment of the pilot's control wheel
sprocket and mating aileron control chain, it will be necessary to perform the following checks at each 100
hour inspection of the airplane.
NOTE
To adequately perform the following checks, the aircraft should
be located in an area relatively free of excessive noise and
vibration.
1. Gently grasp the pilot's control wheel with both hands. Slowly rotate the wheel while carefully
listening for sounds of roughness or the feel of uneven action when the aileron chain links pass over each tooth
of the sprocket.
2. With one mechanic slowly rotating the pilot's control wheel, and another mechanic (with flashlight
and mirror) observing the movement of the aileron chain over the sprocket, observe for smooth flow of the
chain links over the sprocket throughout the total travel of the control wheel.
b. If roughness or uneven action is not felt, heard or seen, no further action is required.
c. If roughness or uneven action is detected, it could be due to lack of lubrication on the chain (if so, dean
and lubricate), bent teeth on the sprocket (if so, sprocket must be replaced) or sprocket/control chain misalignment
that must be corrected as follows:
1. Inspect at outboard end of sprocket housing to determine if the .032 shim is installed between the
offset in the housing and the bulkhead. Install shim if it is not present. This shim will ensure proper horizontal
alignment.
2. To attain proper vertical alignment, install new .012 shims between the top or bottom of the
sprocket housing and the bulkhead, as required, to ensure a smooth flow of the chain links over the sprocket.
3-14 INSPECTION OF PROPELLER HUB. At each 50 hours time-in-service, use a 10X magnifying glass
to inspect propeller hub for cracks.
a. On two blade hubs, cracks originate adjacent to blade "fillet radius". Refer to Piper Service Bulletin
No. 927 and latest revision of Hartzell Service Bulletin No. 164.
b. On three blade hubs, cracks typically originate in the threads in a grease fitting hole on the side of the
hub. Refer to Piper Service Bulletin No. 926 ,latest revision of Hartzell Service Bulletin No. 165, and
Airworthiness Directive No. 93-16-14.
3-15
INSPECTION OF CONTROL CABLES. Refer to latest edition of Advisory Circular 43.13-1A,
paragraph 198 for inspection of control cables procedures.
Revised: 2/18/94
INSPECTION
1D20